Fly ash is a by-product from the burning of coal in coal fired power stations. Fly ash is made in abundance and typically contains heavy metals such as cadmium, chromium, zinc and lead that make disposal problematic. In trying to minimise the environmental impact of fly ash, various uses of fly ash have been contemplated to both aid in fly ash disposal and to obtain some economic return.
One such use is in the manufacture of bricks that contain fly ash as a constituent part. These bricks usually include fly ash blended with clay and are fire hardened. Whilst these bricks find a use for fly ash, they have not been seen as a viable structural building element. In particular, difficulties have been encountered in manufacturing bricks containing fly ash that are cost competitive with existing bricks, are of a consistent quality, and perform adequately over a range of structural properties.